DSpace Collection: Information, School of (SI)

Provision, Interpretation and Effects of Feedback in Reputation Systems.

Mon, 29 Oct 2007 22:58:59 GMT

Title: Provision, Interpretation and Effects of Feedback in Reputation Systems.

Authors: Khopkar, Tapan A.

Abstract: This dissertation addresses three questions that arise out of the voluntary and subjective provision of feedback and its subjective interpretation. The first study is an experimental investigation of a mechanism designed to give buyers incentives for feedback provision. It starts from the intuition that if buyers' feedback giving histories are made available to sellers, reputation effects will arise on the buyer side and act as incentives for buyers to provide more feedback. In a controlled laboratory experiment I examined whether this mechanism had the desired effects on buyer and seller behavior, and found that the mechanism had mixed success. It resulted in higher levels of feedback, but not higher levels of trust, trustworthiness or gains from trade. In the second study, I conducted an empirical analysis of transaction and feedback data from eBay, to understand the impact of a negative feedback in the seller’s profile on his own future behavior, and behavior of the buyers he gets matched with. I found evidence that after sellers got negative feedbacks; they were less likely to list items again, at least for a while. For sellers who continued to sell, the presence of a negative feedback in the recent past made buyers more willing to give another negative feedback. In the third study, I examined the effect of culture on behavior in Reputation Systems. In a controlled laboratory experiment using student subjects having two different nationalities, I found that the differences in trust and trustworthiness between the two groups prevailed in spite of the reputation system. I also found that there were systematic differences in how people from the two groups interpreted comparable reputation profiles.

Why Share in Peer-to-Peer Networks?

Mon, 29 Oct 2007 22:58:59 GMT

Title: Why Share in Peer-to-Peer Networks?

Authors: Jian, Lian; MacKie-Mason, Jeffrey K.

Abstract: Prior theory and empirical work emphasize the enormous free-riding problem facing peer-to-peer (P2P) sharing networks. Nonetheless, many P2P networks thrive. We explore two possible explanations that do not rely on altruism or explicit mechanisms imposed on the network: direct and indirect private incentives for the provision of public goods. The direct incentive is a traffic redistribution effect that advantages the sharing peer. We din this incentive is likely insufficient to motivate equilibrium content sharing in large networks. We then approach P2P networks as a graph-theoretic problem and present sufficient conditions for sharing and free-riding to co-exist due to indirect incentives we call generalized reciprocity.

PEAK: Pricing Electronic Access to Knowledge

Tue, 29 Oct 1996 22:58:59 GMT

Title: PEAK: Pricing Electronic Access to Knowledge

Authors: MacKie-Mason, Jeffrey K.; Jankovich, Alexandra

Some Economics of Market-Based Distributed Scheduling

Tue, 28 Apr 1998 22:58:59 GMT

Title: Some Economics of Market-Based Distributed Scheduling

Authors: MacKie-Mason, Jeffrey K.; Walsh, William E.; Wellman, Michael P.; Wurman, Peter

Abstract: Market mechanisms solve distributed scheduling problems by allocating the scheduled resources according to market prices. We model distributed scheduling as a discrete resource allocation problem, and demonstrate the applicability of economic analysis to this framework. Drawing on results from the literature, we discuss the existence of equilibrium prices for some general classes of scheduling problems, and the quality of equilibrium solutions. We then present two protocols for implementing market solutions, and analyze their computational and economic properties.